+## LINK-BOOST OPTIMIZATIONS
+
+In `--separate` and in `--erasure` modes, some optimization can be gained by hijacking the linker process.
+
+Warning: these optimisations are not portable since they use extra features of the GNU linker `ld`.
+However, there is very few reasons to not use them if GNU `ld` is available.
+
+`--link-boost`
+: Enable all link-boost optimizations.
+
+`--colors-are-symbols`
+: Store colors as symbols instead of static data.
+
+ By default, the various identifiers used to implement OO-mechanisms are stored as genuine constant static variables.
+
+ This option uses linker symbols to encode these identifiers.
+ This makes the compiled program faster since less indirections are required to get the values.
+ It also produces executables that are a little bit smaller since static memory does not have to store the colors.
+
+`--substitute-monomorph`
+: Replace monomorphic trampolines with direct call.
+
+ Late-binding is implemented with *trampolines*, that are small functions that just select and jump the to right implementations.
+ If, at link-time, is it known that the target will always by the same implementation then all calls to the trampoline are replaced by
+ direct calls to this single implementation.
+
+ Note that using trampolines as indirection slows down the executable.
+ However, it is expected that the gain of monomorphic direct-calls overcompensates the additional indirections in polymorphic trampoline-calls.
+
+ Note: automatically enable option `--trampoline-call`.